Progressive power intraocular lens, and methods of use and manufacture

ABSTRACT

Apparatuses, systems and methods for providing improved intraocular lenses (IOLs), include features for reducing side effects, such as halos, glare and best focus shifts, in multifocal refractive lenses and extended depth of focus lenses. Exemplary ophthalmic lenses can include a continuous, power progressive aspheric surface based on two or more merged optical zones, the aspheric surface being defined by a single aspheric equation. Continuous power progressive intraocular lenses can mitigate optical side effects that typically result from abrupt optical steps. Aspheric power progressive and aspheric extended depth of focus lenses can be combined with diffractive lens profiles to further enhance visual performance while minimizing dysphotopsia effects. The combination can provide an increased depth of focus that is greater than an individual depth of focus of either the refractive profile or the diffractive profile.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/293,258 filed Feb. 9, 2016 entitled “ProgressivePower Intraocular Lens, and Methods of Use and Manufacture.” The contentof the above listed application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Embodiments of the present invention relate generally continuous powerprogressive lens surfaces, and particular embodiments provide methods,devices, and systems for mitigating or treating vision conditions suchas presbyopia, often by determining a desired power ranges for theprofile and selecting an aspheric surface that results in a continuouspower progressive lens shape according to the desired power profile andto various parameters of the patient's eye.

In multifocal intraocular lenses (IOLs), multiple optical zones providefor different optical powers at the different zones. The multipleoptical zones can improve the vision of a patient at different viewingdistances, such as near distance, intermediate distance and fardistance. A neuroadaptation phenomenon allows the human brain to choosewhich focused image to rely on out of multiple focal distances provided.Therefore, an implanted intraocular lens with multiple zones can allow apatient to see with improved acuity at multiple viewing distances.However, multifocal intraocular lenses can also reduce the contrast onthe image, and can increase night vision disturbances such as glare andhalo. Moreover, multifocal IOLs can also cause best focus shift underdifferent light conditions.

Although current and proposed multifocal intraocular lenses and relatedmethods provide real benefits to patients in need thereof, still furtheradvances would be desirable. Embodiments of the present inventionprovide solutions to at least some of these outstanding needs.

BRIEF SUMMARY OF THE INVENTION

Embodiments herein described include IOLs with a continuous refractiveaspheric surface that results in a radial power progression. Specificembodiments include IOLs with an aspheric surface defined by a singleaspheric equation that includes certain high order terms. Such IOL's canapproximate some features of a multifocal lens providing a range ofpowers, but without some of the drawbacks associated with multifocallenses. In one example, an aspheric IOL can approximate a first opticalzone across a first region of the IOL and approximate a second opticalzone across a second region of the IOL. The continuous aspheric surfaceof the IOL lacks the discontinuity associated with a multizonal surface.Advantageously, IOL embodiments disclosed herein provide improvedoptical performance in low-light or night viewing conditions by avoidingor reducing side effects, including visual artifacts such as glare andhalo, as well as best focus shifts and contrast sensitivity loss. Visualartifacts are often perceived by patients treated with currentlyavailable multifocal IOLs, and are typically produced by point sourcesof light, such as automobile headlights and traffic or street lights.

IOL embodiments disclosed herein avoid the use of certain physicaltransitions between different optical zones that can otherwise create orexacerbate visual artifacts for the patient. Optical power can bedetermined, e.g., by the optical shape of a lens. In general, opticalpower is related to the second derivative or curvature of an opticalshape. For example, power can be defined in terms of an instantaneousradius of curvature or an axial radius of curvature. In a refractivemultifocal IOL, different regions of a lens surface have differentcurvatures. For example, in certain annular designs, concentric annularoptical zones may each be configured to maintain a different predefinedfocal length to enable multifocal vision. However, the annular zoneswould tend to meet at abrupt changes in curvature. An abrupt opticalpower step between adjacent zones can cause visual artifacts includingglare, halos, and decreased contrast sensitivity. Although the effectsof zone boundaries can be reduced by inserting matching transitionzones, such transitions zones can also introduce dysphotopsia effects.Visual artifacts can be compounded when the number of different zones(and accordingly the number of abrupt optical power steps) is increased.

IOL embodiments according to the present invention avoid the abruptchanges in curvature described above. For example, IOLs having a surfacedefined by a continuous aspheric function, which have a continuous firstderivative and a continuous second derivative, can further reduce oreliminate visual artifacts and other dysphotopsia effects. In somecases, progressive power IOLs having a continuous aspheric surface canachieve visual performance that reduces dysphotopsia effects to levelssimilar to an aspheric monofocal lens. Furthermore, IOL embodimentsaccording to the present invention can provide desirable visualperformance attributes at intermediate viewing distances, whereas somecurrently available IOLs are limited to only providing for near and farvision.

IOL embodiments described herein can be configured to approximatemultizonal designs by having a continuous aspheric curvature fitted to amultizonal surface. In some cases, an IOL can approximate multipleannular zones in a radial power progressive design fitted to an asphericsurface. The continuous power progressive IOLs achieve good visualperformance in both the far and intermediate distances, while reducingvisual artifacts and optical aberrations. In some cases, such IOLs canbe configured to induce or to alleviate specific optical aberrations.For example, a multizonal surface can be fitted to the continuousaspheric surface, thus eliminating abrupt optical steps that wouldotherwise exist between zones, providing improved focal depth atspecified distances for different pupil sizes, or mitigating visualartifacts such as halos, glare, and reduced contrast sensitivity. Inaddition, fitting procedures can generate IOLs that have improvedcosmetic appearance over IOLs with discrete optical zones, thusgenerating IOLs that may be visually indistinguishable from monofocalIOLs.

For IOL embodiments that approximate multizonal configurations, thenumber of zones and power, diameter, and spherical aberration of eachzone can be modified to provide different performance attributes fordistance, intermediate, and/or near vision at different pupil sizes,prior to generating a continuous aspheric lens surface. For example,lens attributes may be adjusted to provide increased depth of focus,i.e. providing acceptable image sharpness for a patient across a greaterrange of distances, without significantly increasing visual artifacts orrefractive errors. Furthermore, lens attributes may be adjusted toincrease depth of focus while taking into account and accommodatingspecific pupil sizes. Also, various designs herein described providecontinuous vision within a range of defocus values, and are thereforemore tolerant than conventional IOLs to residual refractive errorswithin the range. Moreover, IOL embodiments disclosed herein may alsocompensate for best focus shift for different light conditions.

According to some aspects, embodiments of the present invention caninclude systems and methods for generating a continuous aspheric surfacefor use in continuous aspheric implantable lenses. In some cases,methods for generating a continuous aspheric surface can includedefining a first optical zone configured to place a first focal distanceof the intraocular lens a first distance behind the intraocular lens,and defining a second optical zone configured to place a second focaldistance of the intraocular lens, a second distance behind theintraocular lens. The first and second optical zones can be determinedbased on criteria such as, but not limited to, choosing opticalperformance for specific distances or depths of focus, for accommodatinga specific pupil size, or other visual needs.

In embodiments, systems and methods for generating the continuousaspheric surface can include generating the continuous aspheric surfacefrom an elevation profile of the optical zones. The first optical zonecan have an elevation profile that extends from a center of the firstoptical zone to an outer periphery of the first optical zone. The secondoptical zone can have an elevation profile that extends from an innerperiphery of the second optical zone to an outer periphery of the secondoptical zone. An elevation step disposed between the profiles can beeliminated by merging the optical zones at the zone boundary. An opticalpower step disposed between the power profile of the first optical zoneand the power profile of the second optical zone can be eliminated bygenerating the aspheric surface for the intraocular lens based on thefitting of the merged first optical zone and second optical zone.

In embodiments, the aspheric surface may be defined by a single asphericequation, such that the continuous aspheric surface for the intraocularlens approximates aspects of the first optical zone across a firstregion of the intraocular lens and approximates aspects of the secondoptical zone across a second region of the intraocular lens. Suchaspects can include the optical powers across portions of the opticalzones, asphericity and the elevation across portions of the opticalzones. The single aspheric equation can define the continuous asphericsurface such that the optical power of an intraocular lens produced withthe surface varies as a continuous function of the radial distance fromthe center of the intraocular lens, such that there is no optical powerstep along the intraocular lens power profile.

According to some aspects, embodiments of the present invention caninclude systems for making a continuous aspheric implantable lens. Suchsystems can include an input that accepts an ophthalmic lensprescription for a patient eye. Suitable ophthalmic lens prescriptionsmay provide a first optical power or range of powers for defining afirst region of an implantable lens and a second optical power or rangeof powers for defining a second region of the implantable lens. In somecases, prescriptions can provide multiple optical powers or ranges ofoptical powers for defining more than two regions of an implantablelens. Such systems may also include one or more modules for generatingan aspheric curvature based on the ophthalmic lens prescription. In somecases, the aspheric curvature can be configured to fit the merged firstregion and the second region. Such systems may further include amanufacturing assembly, such as a computer-controlled fabricationmodule, that fabricates the intraocular lens based on the asphericcurvature.

According to some embodiments of the present invention, ophthalmiclenses having a continuous aspheric refractive power profile can becombined with diffractive profiles to achieve an extended depth offocus. For example, an ophthalmic lens can have a first surface and asecond surface disposed about an optical axis, the lens beingcharacterized by an extended depth of focus. A refractive profile, whichcan be a continuous aspheric refractive power-progressive profile, isimposed on one of the first surface or the second surface; and adiffractive profile can be imposed on one of the first surface or thesecond surface. In some cases, the diffractive profile and refractiveprofile can be on the same surface; or in some cases they can be onopposite surfaces. For example, in some embodiments, diffractive andrefractive profiles can be on a posterior surface; or in otherembodiments, the diffractive profile can be on a posterior surface andthe refractive profile on the anterior surface. The diffractive profileincludes at least one set of diffractive zones that partially correctsfor ocular chromatic aberration. The combination of the refractiveprofile and diffractive profile provides an increased depth of focusthat is greater than an individual depth of focus of either therefractive profile or the diffractive profile.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a multizonal surface and an analogous progressivepower lens approximating the multizonal surface in a front view, inaccordance with embodiments;

FIG. 2 illustrates elevation profiles of the multizonal surface and theanalogous progressive power lens of FIG. 1;

FIG. 3 illustrates a difference between the elevation profiles shown inFIG. 2 in more detail;

FIG. 4 illustrates power profiles of the multizonal surface and ananalogous progressive power lens of FIG. 1;

FIG. 5 illustrates a difference between the power profiles of themultizonal surface and an analogous progressive shown in FIG. 4;

FIG. 6 illustrates the difference between the power profiles of themultizonal surface and an analogous progressive shown in FIG. 4 in termsof the relative power over the second zone;

FIG. 7A shows the simulated visual acuity of three example lenses for apupil size of 3 mm;

FIG. 7B shows the simulated VA of the example lenses of FIG. 7A for apupil size of 5 mm;

FIGS. 8A-8B show the simulated visual acuity of an additional examplelens for pupil sizes of 3 mm and 5 mm, respectively, similar to FIGS.7A-7B;

FIG. 9 shows a simulated VA for two example progressive power lenseswith reference to a comparative monofocal aspheric lens;

FIG. 10 illustrates a three-zone multizonal surface and an analogousprogressive power lens based on the multizonal surface in a front view,in accordance with embodiments;

FIGS. 11A-11B show the simulated visual acuity two additionalprogressive power lens surfaces having varying relative powers in thecentral region respect to the base power of the lens, in comparison toexample lenses shown in FIGS. 7A-7B, for pupil sizes of 3 mm and 5 mm,respectively;

FIGS. 12A-12B show the simulated visual acuity of additional progressivepower lens surfaces having varying asphericity in their peripheryregions, in comparison to example lenses shown in FIGS. 7A-7B and11A-11B, for pupil sizes of 3 mm and 5 mm, respectively;

FIG. 13 illustrates simulated visual acuities of a various lensesincluding a monofocal lens, a multifocal lens, and three powerprogressive lens surfaces;

FIGS. 14A-14B illustrate simulated contrast sensitivity of the variouslenses of FIG. 13 for a 3 mm pupil and 5 mm pupil, respectively;

FIG. 15A illustrates the intensity of refractive artifacts produced by aselection of progressive power lens surfaces compared to an asphericmonofocal lens surface and diffractive multifocal lens surface;

FIG. 15B shows a comparison of halos associated with a progressive powerlens surface and an aspheric monofocal lens surface;

FIG. 16 illustrates the power profile of a refractive power-progressivelens compared to a spherical lens power profile;

FIG. 17 shows simulated VA of an example of a refractive, powerprogressive EDF lens with reference to the simulated VA of a sphericallens;

FIG. 18 illustrates power profiles of two example refractive powerprogressive lenses having different power profiles, with reference to aspherical lens power profile;

FIG. 19 illustrates power profiles of two example refractive, powerprogressive lenses positioned on the anterior and posterior sides of alens, with reference to a spherical lens power profile;

FIG. 20 is a graphical representation illustrating aspects of adiffractive component of a first combined asphericrefractive/diffractive lens profile, according to some embodiments;

FIG. 21 shows simulated VA of a first example of a combined powerprogressive/diffractive extended depth of focus (EDF or EDOF) lens withreference to component lenses having a power progressive and having adiffractive profile, according to some embodiments;

FIG. 22 shows simulated VA of a second example of a combined powerprogressive/diffractive extended depth of focus (EDF or EDOF) lens withreference to component lenses having a power progressive and having adiffractive profile, according to some embodiments;

FIG. 23 is a graphical representation illustrating aspects of analternative embodiment of a diffractive component of a combined asphericrefractive/diffractive lens profile according to some embodiments;

FIG. 24 shows simulated VA of an example combined powerprogressive/diffractive EDF lens with comparative plots illustratingsimulated VA of a power progressive lens and of a diffractive EDF lens,according to some embodiments;

FIG. 25 shows simulated VA of example combined powerprogressive/diffractive EDF lenses, according to some embodiments;

FIG. 26 is a simplified block diagram illustrating a system forgenerating a continuous progressive lens surface, in accordance withembodiments; and

FIG. 27 illustrates an example process for generating a continuousprogressive lens surface; and

FIG. 28 illustrates an example computing environment for facilitatingthe systems and processes of FIGS. 26 and 27.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments herein disclosed relate to lenses having refractivepower-progressive profiles, e.g., lenses having a refractive asphericprofile that provides a continuous power progression to extend depth offocus (EDF). Some embodiments herein disclosed relate to lenses havingrefractive power-progressive profiles in conjunction with diffractiveprofiles, which provide improved depth of focus to a patient. Accordingto some embodiments, a diffractive lens can partially correct for ocularchromatic aberration.

Embodiments of lenses herein disclosed can be configured for placementin the eye of a patient and aligned with the cornea to augment and/orpartially replace the function of the crystalline lens. In someembodiments, corrective optics may be provided by phakic IOLs, which canbe used to treat patients while leaving the natural lens in place.Phakic IOLs may be angle supported, iris supported, or sulcus supported.IOLs can be further secured with support members that attach the IOL tothe eye, e.g., with physical extensions from the IOL into adjacentcorneal or iris tissue. Phakic IOLs can also be placed over the naturalcrystalline lens or piggy-backed over another IOL. Exemplary ophthalmiclenses include contact lenses, phakic lenses, pseudophakic lenses,corneal inlays, and the like. It is also envisioned that the lens shapesdisclosed herein may be applied to inlays, onlays, accommodating IOLs,spectacles, and even laser vision correction.

In various embodiments, an intraocular lens can include a first regionhaving a nonzero relative power respect to the base power of the lensand a second region defining a base power that extends to the peripheryof the lens. The first region can be radially symmetric about an opticalaxis of the lens and extend part of a distance from the axis to theperiphery. The second region can be an aspheric surface which extendsfrom the outer diameter of the first region to the lens periphery. Thesecond region can have a relative power of approximately zero throughoutsubstantially all of the zone while exhibiting aspheric profileconfigured to match the elevations of the first region at the firstregion outer diameter, such that the first and second regions mergesmoothly at the boundary between the zones. In embodiments, the firstand second regions can be described by a unique surface function, suchthat there are no discontinuities or abrupt breaks in an add profileacross the lens. Regions can be defined as portions of the lensdescribed by the radius of the zones that are fitted to the asphericequation. Therefore, region boundaries need not equate to physicalboundaries because the lens has a continuous curvature. However, thesurface function can include high-order terms in order to provideoptical properties that functionally approximate an intraocular lenshaving discrete optical zones.

In various embodiments, an intraocular lens can include regions inaddition to the first and second regions that have nonzero relativepowers respect to the base power of the lens. In one example, a firstregion can include a range of relative powers for providing near visionin a patient with presbyopia, and a second region can include a range ofrelative powers for correcting intermediate vision in the same patient.The first and second regions can be positioned in a radially symmetricmanner about an optical axis, with the third region being positionedaround the first and second regions. The third region, which can bedefined by the same surface function which defines the first and secondregions, can define the base power of the lens (i.e. have an relativepower of approximately zero) throughout substantially all of the zonewhile exhibiting aspheric curvature configured to match the elevationsof the second region, such that the second and third regions mergesmoothly. Elevations resulting from merging the first, second and thirdzones are determined, and then fitted to a unique aspheric surface. Thecontinuous aspheric surface approximates some attributes of the originalzones, but results in a continuous surface that prevents or mitigatesdysphotopsia and optical effects that would ordinarily result fromconnecting discrete optical zones. In some other embodiments, multipleintermediate regions having different optical power ranges can beprovided between the center of an intraocular lens and its periphery.

Exemplary Intraocular Lens Shapes Approximating 2-Zone Surface:

Turning now to the drawings, FIG. 1 illustrates a multizonal surface 102and an analogous, continuous power progressive intraocular lens surface104 based on the multizonal surface in a front view, in accordance withembodiments. The multizonal surface 102 includes two concentric lenssurfaces defining a first zone 108 that is concentric and radiallysymmetric about an optical axis 122, and a second zone 112 that isconcentric with the first zone and also radially symmetric about theoptical axis. The original, multizonal surface can be describedaccording to the following dimensions in Table 1:

TABLE 1 Lens parameters of an exemplary multizonal lens. Zone 1(spherical) Relative Zone 2 (aspheric) power Extension (diameter)Relative power Extension (diameter) 2.3 D 1 mm 0 D 5 mm

Each zone can be defined according to the aspheric equation for lenssag, as follows:

$\begin{matrix}{{{High}\text{-}{order}\mspace{14mu}{aspheric}\mspace{14mu}{equation}\mspace{14mu}{for}\mspace{14mu}{an}\mspace{14mu}{intraocular}\mspace{14mu}{{lens}.Z}} = {\frac{{cr}^{2}}{1 + \sqrt{1 - {( {k + 1} )c^{2}r^{2}}}} + {a_{2}r^{2}} + {a_{4}r^{4}} + {a_{6}r^{6}} + {a_{8}r^{8}} + {a_{10}r^{10}} + {a_{12}r^{12}} + z_{0}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In the equation above ‘r’ is the radial distance in mm, ‘c’ is thecurvature in mm⁻¹, ‘k’ is the conic constant, and a₂, a₄, a₆, a₈, a₁₀,a₁₂ are aspheric coefficients; and z₀ is an elevation parameterreferring to an elevation of the aspheric surface. The elevationparameters of two or more surfaces may be adjusted without changing theshapes of the surfaces to smoothly merge both zones, such that anelevation step that may be present between the two zones is eliminated.This parameter directly depends on the geometry of both zones at theinner diameter of the second zone. In embodiments, each zone may bedescribed as an even asphere, such that the zones are radiallysymmetric.

Each of the zones in the discontinuous multizonal surface 102 can bedefined individually according to the coefficients of the lens equationabove. For example, a spherical surface (e.g. zone 1) can be definedwhere all of the coefficients of the equation, except the curvature, arezero, and the aspheric surface can be defined where a number of thecoefficients are nonzero. By way of example, the multizonal lens surface102 can be described according to the coefficients of Table 2 below.

TABLE 2 Exemplary geometry of a multizonal lens surface. Relative powerdiameter r k a₄ a₆ a₈ a₁₀ a₁₂ Zone 1 2.3 D 1 mm 9.7 0 0 0 0 0 0 Zone 2 0D 5 mm 11.6 −1.0 −7.3E−04 −9.3E−04 0 0 0

The radius of the first zone (R) can be related to the relative power(RP) according the equation 2, below, where R_(post) is the radius ofthe posterior surface, d is the central thickness of the lens, P_(base)the base power and n_(L) and n_(m) are the refractive index of the lensand the media, respectively. The radius of the second zone can becalculated so that in combination with that of the posterior surface,thickness and refractive index of the lens and surrounding media providewith the base power as defined in Table 2.

$\begin{matrix}{{{Equation}\mspace{14mu}{for}\mspace{14mu}{determining}\mspace{14mu}{radius}\mspace{14mu}{of}\mspace{14mu}{curvature}\mspace{14mu}{as}\mspace{14mu} a}\mspace{14mu}{{function}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{relative}\mspace{14mu}{power}\mspace{14mu}({RP})}{R = {\frac{1000}{n_{L}{R_{post}( {\frac{1000}{R_{post}} + \frac{P_{base} + {RP}}{n_{L} - {nm}}} )}}( {{n_{L}R_{post}} + {( {n_{L} - {nm}} )d}} )}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

Alternatively, the radius of the first zone can be calculated from therelative power (RP) and the radius of the second zone (R_(z)) fromEquation 3, below:

$\begin{matrix}{{{Determining}\mspace{14mu}{the}\mspace{14mu}{radius}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{first}\mspace{14mu}{{zone}.R}} = \frac{1000}{\frac{1000}{R_{z}} + \frac{RP}{n_{L} - n_{m}}}} & {{Equation}\mspace{14mu} 3}\end{matrix}$

The continuous power progressive lens surface 104, unlike the multizonalsurface 102, is defined by a single aspheric equation that is configuredto approximate elevations of the multizonal surface and can be describedby Equation 1. Although the multizonal surface can be derived by mergingthe edges of the first and second zones (e.g., by matching an elevationof the outer perimeter of Zone 1 with an inner perimeter of Zone 2) sothat a height profile is continuous from the central or optical axis ofthe lens to the outer periphery, the slope of the multizonal lens is notcontinuous, which causes the power profile to have a sharp discontinuityas well.

Table 3, below, describes the geometry of the exemplary continuous powerprogressive lens surface based on the multizonal lens surface describedin Table 2, once fitted to a unique aspheric surface defining acontinuous progressive lens surface.

TABLE 3 Geometry of an exemplary continuous power progressive lenssurface. r k a₄ a₆ a₈ a₁₀ a₁₂ 9.7 1.8E+00 −1E−02 6E−03 −2E−03 2E−04−1E−05

In FIG. 1, the multizonal lens 102 includes a first zone 108 defined bythe first zone outer perimeter 106, and a second zone 112, which isdefined between the first zone outer perimeter 106 and the lensperiphery 110. In some cases, as illustrated in this example, the firstzone 108 may be a spherical surface having a constant optical power fromthe center 122 of the lens 102 to the first zone outer perimeter 106.The second zone 112 can be an aspheric surface having a gradual changein the optical power from the first zone outer perimeter 106 to the lensperiphery 110.

The structure of the continuous power progressive lens surface 104differs from the multizonal surface 102 as follows, in accordance withembodiments. Instead of a stark boundary between first and second zones,a first region 116 blends continuously into a second region 120. Aregion boundary 114 is eliminated and the slope of the lens surface fromthe first region 116 to the second region 120 changes gradually overradial distance from the center 124 of the continuous power progressivelens surface 104 to the periphery 118. However, the aspheric equationdefining the continuous power progressive lens surface 104 canapproximate multiple optical regimes across the surface. For example,the first region 116 can approximate attributes of the spherical firstzone 108, e.g. by providing an equivalent optical power across at leastpart of the first region 116. The second region 120 can likewise providean optical power across at least a portion of the second region that isapproximately equivalent to an optical power of the second zone 112.

FIG. 2 shows an elevation profile 206 of the continuous powerprogressive lens surface 104 overlaid on the elevation profile of themultizonal lens 102 (FIG. 1), in accordance with embodiments. Thecontinuous power progressive lens surface 104 appears similar to themultizonal lens 102 with subtle differences that are more readilyvisible by mapping the elevation difference 306 between the two lenssurfaces, as shown in FIG. 3. The continuous power progressive lenssurface 104 closely approximates the multizonal lens 102 where theelevation difference is zero, e.g., at a radial distance of zero (thelens center), and is most different from the multizonal lens near afirst boundary 202 between the first and second zones, e.g. at a radialdistance of 0.5 mm, where the smooth geometry of the continuous powerprogressive lens surface 104 differs from the discontinuous slope of themultizonal lens 102, and at an outer periphery 204.

Although the elevation differences between the multizonal surface 102and the analogous continuous progressive lens surface 104 (FIG. 1) aresubtle, the effects of the different elevation profiles may be morereadily understood by referring to a comparison between the powerprofiles of the lenses.

FIG. 4 illustrates the multizonal power profile 408 of the multizonalsurface 102 and the analogous continuous progressive power profile 406of the continuous progressive lens surface 104 shown in FIG. 1. Themultizonal surface (2-zones) is characterized by a constant opticalpower of greater than 22 diopters in Zone 1 from a radial distance of 0with respect to the optical axis of the intraocular lens to a radialdistance of 0.5 mm, which defines the outer perimeter 202 of the firstzone. The optical power is discontinuous at the radial distance of 0.5mm, and thereafter follows a diminishing power profile according to theaspheric surface of Zone 2. In the continuous progressive lens surface(asphere), the optical power at the lens center is approximately equalto the power of Zone 1. The power profile of the continuous progressivelens surface 406 (asphere) decreases without a discontinuity toapproximate the optical power of Zone 2.

FIG. 5 illustrates the difference in power profiles 506 between themultizonal surface 102 and the analogous continuous progressive lenssurface 104 (FIG. 1) as shown in FIG. 4, in greater detail. The powerprofiles are most closely matched at the lens center (radial distance=0)and in a majority of the second region 120 (FIG. 1), with the greatestdifference in power profiles near the power profile discontinuity at thefirst zone boundary 202.

By way of further example, FIG. 6 illustrates the power profiledifference of a power progressive aspheric lens 606 and the 2-zonalsurface 608, normalized with respect to a power profile of a standardaspheric monofocal surface. The 2-zonal lens power profile 608 andaspheric power progressive lens power profile 606 relate, respectively,to the 2-zone lens surface 102 and the analogous continuous progressivelens surface 104 shown in FIG. 1. FIG. 6 illustrates that the powerprofile of the continuous progressive lens surface differs from both astandard, monofocal aspheric profile and from a multizonal surface 102.

In various embodiments, the size of a central region of a continuousprogressive lens surface can be increased, obtaining similar results toincreasing the size of a central zone of a multizonal surface. Forexample, Table 4 below illustrates two different designs that have twozones, similar to the multizonal surface 102 (FIG. 1).

TABLE 4 Lens parameters of example lens surfaces A1 and A2 Zone 1(spherical) Zone 2 (aspheric) Lens Relative Extension Relative ExtensionDesign power (diameter) power (diameter) A1 1.75 D 1.5 mm 0 D Rest oflens A2 1.75 D 1.3 mm 0 D Rest of lens

In lens designs A1 and A2 referenced above in Table 4, the central zone(Zone 1) is spherical and the peripheral zone (Zone 2) is aspheric. Zone1 and 2 of designs A1 and A2 have the same geometry (same maximumrelative power in the central zone (−1.75 D) and same base power in theperipheral zone (0 D)). However, the central zone has differentextension (either 1.3 mm or 1.5 mm diameter). Table 5, below, describesthe geometry of each zone for both designs, in terms of curvature andhigher order aspheric terms. It should be noted that although bothdesigns are based on the same geometrical parameters for defining thetwo zones (Table 5), the final designs differ (Table 6) because of thedifferences in the size of the central zone.

TABLE 5 Lens parameters of example lens surfaces A1 and A2 r k a₄ a₆ a₈a₁₀ a₁₂ A1 Zone 1 10.1 0.0E+00  0E+00  0E+00 0E+00 0E+00 0E+00 Zone 211.7 1.1E+00 −7E−04 −1E−05 0E+00 0E+00 0E+00 A2 Zone 1 10.1 0.0E+00 0E+00  0E+00 0E+00 0E+00 0E+00 Zone 2 11.6 1.1E+00 −7E−04 −1E−04 0E+000E+00 0E+00

Table 6, below, describes the geometry of both designs A1 and A2 oncefitted to a unique aspheric surface defining a continuous progressivelens surface.

TABLE 6 Geometry of the fitted aspheric surfaces generated from lensesA1 and A2 r k a₄ a₆ a₈ a₁₀ a₁₂ A1 9.9  6.5E−03 −4E−03 −1E−03 4E−04−9E−05 6E−06 A2 10.0 −6.0E−04 −5E−03  1E−03 6E−05 −4E−05 3E−06

Varying the extension of the central region as described above beforegenerating the continuous progressive lens surface can change theperformance of the lens. For example, adjusting the extension of thecentral region can change the defocus performance of the lens.

By way of example, FIGS. 7A-B illustrate the simulated visual acuity oflenses A1 706 and A2 704, with an exemplary monofocal aspheric lens 702for comparison purposes, for 3 mm and 5 mm pupil sizes respectively.Visual acuity is calculated according to methods described in U.S.patent application Ser. No. 14/878,294 entitled, “Apparatus, Systems andMethods for Improving Visual Outcomes for Psuedophakic Patient,” whichis hereby incorporated by reference. FIG. 7A shows the simulated visualacuity (VA) of the example lenses for a pupil size of 3 mm, and FIG. 7Bshows the simulated VA of the example lenses for a pupil size of 5 mm.

FIGS. 7A-7B demonstrate that adding the central region (the region ofthe continuous progressive lens surface derived from Zone 1 of themultizonal surfaces) increases depth of focus. In particular, the depthof focus is increased over the monofocal model, as shown by theincreased depth of focus of the continuous progressive lens curves 706,704 (for A1 and A2, respectively) over the monofocal depth of focuscurve 702 for the exemplary monofocal surface (FIGS. 7A, 7B). For thelens designs of FIGS. 7A-7B the depth of focus is increased with respectto that of the monofocal aspheric lens. The impact of the central zonesize is also more readily apparent for the smaller pupil than for thelarger pupil. FIGS. 7A-7B demonstrate that the best focus (defocusposition with the best visual acuity) of the progressive lens A1 and A2does not change with the pupil size.

Performance can also be modified by changing the asphericity of thecontinuous progressive lens surface near the periphery of the lens in anintraocular lens based on two zones. For example, Tables 6-8, below,illustrate aspects of another example of a multizonal lens surface and acontinuous progressive lens surface derived therefrom. Table 7 describesthe parameters of the third example surface A3. Table 8 describes thegeometry of each zone of a multizonal surface conforming to theparameters of Table 7. As illustrated by Table 8, A3 only differs fromA2 in the conic constant and higher order aspheric terms describing thesecond zone. The second zone of A3 resulted in a surface that inducesnegative spherical aberration, but does not fully compensate for that ofthe cornea. Table 9 describes the geometry of an aspheric surfacedefining a continuous progressive lens surface based on the multizonalsurface described in Table 8.

TABLE 7 Lens parameters of the third example surface A3 Zone 1(spherical) Zone 2 (aspheric) Lens Relative Extension Relative ExtensionDesign power (diameter) power (diameter) A3 1.75 D 1.30 mm 0 D Rest oflens

TABLE 8 Geometry of the multizonal surface of lens A3 r k a₄ a₆ a₈ a₁₀a₁₂ A3 Zone 1 10.1 0.0E+00  0E+00  0E+00 0E+00 0E+00 0E+00 Zone 2 11.61.8E+00 −6E−04 −1E−05 0E+00 0E+00 0E+00

TABLE 9 Geometry of the fitted aspheric surface generated from lens A3 rk a₄ a₆ a₈ a₁₀ a₁₂ A3 9.6 5.0E−03 −1E−02 5E−03 −1E−03 2E−04 −8E−06

FIGS. 8A-8B demonstrate that changing the asphericity in the peripherydoes not significantly affect the optical performance (visual acuity)for smaller pupil sizes. Note that, in FIG. 8A, the A3 curve 802 doesnot differ significantly from the A2 curve 704. However, at larger pupilsizes, as shown in FIG. 8B, the A3 lens increases the depth of focusover the A2 lens. In particular, the depth of focus is further increasedover the monofocal model, as shown by the increased depth of focus ofthe A3 lens curve 802 over the monofocal depth of focus curve 702 forthe exemplary monofocal surface. A spherical aberration for theperipheral zone can be selected, and then the peripheral zone can bedesigned based on the amount of asphericity indicated.

Extended Depth of Focus

Embodiments herein disclosed also relate to lenses having a refractiveaspheric profile that provides a continuous power progression to providean extended depth of focus (EDF). The sag of power progressive designsherein disclosed is described by Equation 1. The power progression canbe imposed on the anterior or on the posterior lens surface. Table 10describes a range of values for the parameters describing powerprogressive refractive profiles on an anterior lens surface for a baselens power of 20 D. Furthermore, a power progressive surface may beapplied to the posterior lens surface instead of, or in addition to, theanterior lens surface.

TABLE 10 Range of values for lens sag coefficients describing the powerprogression applied on an anterior side of an ophthalmic lens LowerUpper limit limit R −8 12 k −5 7 a₄ −0.02 0 a₆ −0.003 0.01 a₈ −0.0030.002 a₁₀ −0.0003 0.0003 a₁₂ −1.0E−04 1.0E−04

By way of example, Table 11 describes the geometry of two progressive inpower surfaces that provide EDF. FIG. 9 is a graphical illustration 900that shows the simulated visual acuity imparted by the lenses describedin Table 11. As shown, both lenses Example 1 (904) and Example 2 (906)provide high visual acuity compared to a comparative, monofocal asphericlens 902 throughout an extended focal depth. This visual acuity datademonstrates that the lenses impart extended depth of focus with respectto a monofocal IOL.

TABLE 11 Geometry of the fitted aspheric surfaces of Example Lenses 1and 2 (FIG. 9) r k a₄ a₆ a₈ a₁₀ a₁₂ Example 1 9.0E+00 −4.8E−03 −1.3E−025.8E−03 −1.4E−03 1.7E−04 −8.0E−06 Example 2 9.7E+00 −5.5E−01 −1.2E−025.7E−03 −1.4E−03 1.7E−04 −8.1E−06

The range of coefficients described in Table 11 are applicable forrefractive power progressive profiles with a base power of 20 D. For anygiven design aspheric progressive in power design, the full range of IOLpowers can be expanded. By way of example, Table 12 shows a range ofcoefficient values describing an aspheric power progressive surfaceapplied to an anterior side of an ophthalmic lens for a range of basepowers between approximately 0 D and 50 D. In specific embodiments, therange of base powers can be between 0 D and 50 D, or preferably between0 D and 40 D, or more preferably from about 5 D to about 34 D, fromabout 10 D to 30 D, or from 16 D to 28 D.

TABLE 12 Range of values for lens sag coefficients describing a powerprogression applied on an anterior side of an ophthalmic lens LowerUpper limit limit R 4 29 k −3 13 a₄ −0.02 0 a₆ 0 0.01 a₈ −0.003 0 a₁₀ 00.0003 a₁₂ −1.0E−04 0

Exemplary Intraocular Lens Shapes Approximating 3-Zone Surface:

FIG. 10 illustrates a 3-zone multizonal surface 1002 and an analogous,continuous power progressive lens surface 1004 based on the multizonalsurface in a front view, in accordance with embodiments. Unlike thetwo-zone multizonal surface 102 of FIG. 1, the surface 1002 includesthree concentric lens surfaces defining a first zone 1006 that isconcentric and radially symmetric about an optical axis 1012, a secondzone 1008 that is concentric with the first zone and also radiallysymmetric about the optical axis, and a third zone 1010 that isconcentric with the first and second zones, and radially symmetric aboutthe optical axis. The first and second zones 1006, 1008 meet at a firstzone boundary 1014. The second and third zones 1008, 1010 meet at asecond zone boundary 1016. The third zone 1010 extends to the lensperiphery 1018.

The continuous power progressive lens surface 1004 based on theabove-described multizonal lens surface is defined by a single asphericequation based on Equation 1, described above. The continuous powerprogressive lens surface 1004 can be described in terms of regions thatapproximate elevations of the multizonal surface. For example, a firstregion 1020, a second region 1024, and a third region 1026 areconcentric about the optical axis 1028 and radially symmetric. Thefirst, second, and third regions 1020, 1024, 1026 can be nominallydefined by the first region boundary 1030, second region boundary 1032,and lens periphery 1034. However, and unlike the multizonal surface 1002from which the continuous power progressive lens surface is derived,there are no discontinuities in the slope of the elevation profile ofthe continuous power progressive lens surface between the lens center1028 and periphery 1034.

Varying Central Zone Relative Power in Three Zones:

Implementing designs based on three or more zones can provide forimproved depth of focus at various distances, in accordance withembodiments. For example, Tables 13-15 below describe attributes ofdesigns having three zones or regions. Table 13 describes the parametersof various exemplary three-zone multizonal lens surfaces. Table 14describes the geometry of each multizonal surface conforming to theparameters of Table 13. Table 15 describes the geometry of each asphericsurface defining a continuous progressive lens surface based on themultizonal surfaces described in Table 14.

TABLE 13 Parameters of exemplary 3-zone multizonal lens surfaces. Zone 1Zone 2 Zone 3 Relative Extension Relative Extension Relative ExtensionPower (Diameter) Power (Diameter) Power (Diameter) H10 2.75 D 0.75 mm1.75 1.5 mm 0 Rest I10 1.75 D 0.75 mm 0.75 1.5 mm 0 Rest J10 2.25 D 0.75mm 1.25 1.5 mm 0 Rest

In all cases above, the middle zone has a positive relative power overthe peripheral zone (zone 3) different from the base power of the lens,and the central zone (zone 1) has a positive relative power that is onediopter higher than the intermediate zone (zone 2). All zones have thesame extension for all the designs, 0.75 mm (diameter) and 1.5 mm forthe first and second zones, respectively. As described above for the2-zone cases, each individual zone can be described according toEquation 1, as described below according to Table 14.

TABLE 14 Lens parameters of example lens surfaces H10, I10, J10 beforefitting. r k a₄ a₆ a₈ a₁₀ a₁₂ H10 zone 1 9.4 0 0 0 0 0 0 zone 2 10.8 0 00 0 0 0 zone 3 11.6 1.1 −7E−04 −1E−05 0 0 0 I10 zone 1 10.1 0 0 0 0 0 0zone 2 10.9 0 0 0 0 0 0 zone 3 11.6 1.1 −7.2E−04  −1E−05 0 0 0 J10 zone1 9.7 0 0 0 0 0 0 zone 2 10.5 0 0 0 0 0 0 zone 3 11.6 1.1 −7E−04 −1E−050 0 0

Table 15, below, describes the geometry of power progressive lenssurface designs H10, I10, and J10 once fitted to a unique asphericsurface defining a continuous power progressive lens surface.

TABLE 15 Geometry of the fitted aspheric surfaces generated for lensesH10, I10, J10. r k a₄ a₆ a₈ a₁₀ a₁₂ H10 9.0 4.5E−03 −1E−02 6E−03 −1E−032E−04 −8E−06  I10 10.4 8.9E−03 −4E−03 5E−04  1E−04 −4E−05  3E−06 J10 9.8−5.1E−03  −7E−03 2E−03 −3E−04 7E−06 7E−07

Varying the relative power of the central zone and intermediate zonewith respect the base power of the peripheral zone can change theperformance of the continuous power progressive lens surface resultingof the fitting, as shown in FIGS. 11A-11B.

By way of example, FIGS. 11A-B illustrate the simulated visual acuity oflenses H10, I10, and J10, with the exemplary monofocal aspheric lens 702for comparison purposes, for 3 mm and 5 mm pupil sizes respectively.FIG. 11A shows the simulated visual acuity (VA) of the example lensesfor a pupil size of 3 mm, and FIG. 11B shows the simulated VA of theexample lenses for a pupil size of 5 mm.

FIGS. 11A-11B demonstrate that a more positive relative power at thecentral region increases depth of focus of the continuous powerprogressive lens surface resulting of the fitting. In particular, thedepth of focus is increased over the monofocal model, as shown by theincreased depth of focus of the continuous progressive lens curves 1102,1104, and 1106 (for H10, I10, and J10, respectively) over the monofocaldepth of focus curve 702 for the exemplary monofocal surface. The impactof the central zone positive power respect to the basic power is alsomore readily apparent for the smaller pupil than for the larger pupil.It is also possible to change the behavior of the continuous powerprogressive lens surface resulting of the fitting by changing the powerin the outer zone of the initial multizonal design.

Varying Asphericity in the Periphery:

Changing the asphericity in the periphery can also allow for eitherincreasing the depth of focus for large pupil sizes (i.e. when inducingmore positive spherical aberration) or improving distance image quality.For example, Tables 16-17 below describe attributes of designs havingthree zones or regions, with varying degrees of peripheral asphericity.

Table 16 describes the parameters of exemplary three-zone multizonallens surfaces with varying peripheral asphericity. The designs areordered by decreasing spherical aberration at zone 3.

TABLE 16 Parameters of 3-zone multizonal lens surfaces with varyingspherical aberration. Zone 1 Zone 2 Zone 3 Rel- Exten- Rel- Exten- Rel-Exten- ative sion ative sion ative sion Pow- (Diam- Pow- (Diam- Pow-(Diam- er eter) er eter) er eter) z12 H3 2.75 D 0.75 mm 1.75 D 1.5 mm 0rest +0.11 H8 2.75 D 0.75 mm 1.75 D 1.5 mm 0 rest 0 H9 2.75 D 0.75 mm1.75 D 1.5 mm 0 rest −0.135 H10 2.75 D 0.75 mm 1.75 D 1.5 mm 0 rest −0.2H7 2.75 D 0.75 mm 1.75 D 1.5 mm 0 rest −0.27

Table 17, below, describes the geometry of the designs of Table 16 oncefitted to a unique aspheric surface defining a continuous powerprogressive lens surface.

TABLE 17 Geometry of fitted aspheric surfaces generated for lenses H3,H8, H9, H10, and H7 r k a₄ a₆ a₈ a₁₀ a₁₂ H3 9.1 −1.3E−02 −1E−02 6E−03−1E−03 2E−04 −8E−06 H8 9.1 −1.6E−02 −1E−02 6E−03 −1E−03 2E−04 −8E−06 H99.1 −9.6E−03 −1E−02 6E−03 −1E−03 2E−04 −8E−06 H10 9.0  4.5E−03 −1E−026E−03 −1E−03 2E−04 −8E−06 H7 9.0 −4.8E−03 −1E−02 6E−03 −1E−03 2E−04−8E−06

Changing the asphericity in the periphery of the initial multizonalsurface can improve the depth of focus for larger pupils (i.e., byinducing more positive spherical aberration) of the continuous powerprogressive lens surface resulting of the fitting, and can also improvedistance image quality (i.e., by inducing a larger amount of negativespherical aberration).

By way of example, FIGS. 12A-B demonstrate the effects of changingspherical aberration at the periphery of the initial multizonal surfaceon the simulated visual acuity of the continuous power progressive lenssurface resulting of the fitting described in Tables 16 and 17, alongwith the exemplary monofocal aspheric lens 702 for comparison purposes.Note that the H10 curve 1102 for lens H10 is repeated from FIGS. 11A-B.FIG. 12A shows the simulated visual acuity (VA) of the example lensesfor a pupil size of 3 mm, and FIG. 12B shows the simulated VA of theexample lenses for a pupil size of 5 mm.

FIGS. 12A-12B demonstrate that all five continuous power progressivelens surface lenses display an increased depth of focus over themonofocal model, as shown by the increased depth of focus of thecontinuous progressive lens curves 1202, 1204, 1206, 1102, and 1208 (forH3, H8, H9, H10, and H7, respectively) over the monofocal depth of focuscurve 702 for the exemplary monofocal surface. The impact of changingthe asphericity is more readily apparent for the larger pupil than forthe smaller pupil, as illustrated by the greater spread between thecurves in FIG. 12B. Note that the H3 curve 1202 provides a particularlylarge depth of focus compared to the lenses with negative or zeroperimeter spherical aberration on the initial multizonal zone.Conversely, the H7 curve 1208, illustrative of an intraocular lens witha particularly negative spherical aberration, provides a comparativelyhigh distance image quality. By selecting the spherical aberration inthe peripheral area, an intraocular lens can be tuned to balancedistance visual quality and depth of focus so as to suit a patient witha particular visual need or a lifestyle preference, e.g. a patient whoprefers to prioritize distance vision, intermediate vision, or nearvision.

FIG. 13 illustrates the simulated visual acuity of various lenses withrespect to the optical power. Exemplary curves shown include a referenceaspheric monofocal 702, two of the three-region power progressive lenssurfaces 1202 and 1208 (referring to lens surfaces H3 and H7 describedabove with reference to Tables 16-17 and FIGS. 12A-12B), a 2-regionaspheric power progressive lens surface 1302, and an exemplary standarddiffractive multifocal lens 1304.

FIG. 13 demonstrates improved optical performance of power progressivelenses 1202, 1208, 1302, and a diffractive multifocal lens 1304 over themonofocal aspheric lens 702 in terms of depth of focus for a pupil sizeof 3 mm. Additionally, performance at intermediate distances is improvedin the fitted, aspheric power progressive lens surfaces 1202, 1208, and1302 over the multifocal lens 1304. The visual acuity at far andintermediate distances for the multifocal lens 1304 is shown to besignificantly lower than the visual acuity for the aspheric multifocalpower progressive lenses.

FIGS. 14A and 14B illustrate the simulated contrast sensitivity at 12cycles per degree (cpd) for each of the lenses described above withrespect to FIG. 13, for a 3 mm pupil and 5 mm pupil, respectively. FIG.14A demonstrates that comparable distance contrast sensitivity isobtained between the example monofocal aspheric lens 702 and theaspheric power progressive lenses 1202, 1208, 1302, and 1304, while thestandard diffractive multifocal lens 1304 provides less contrastsensitivity, for 3 mm pupils. FIG. 14B demonstrates that the effect oflens selection is greater for large (5 mm) pupil sizes, with thestandard diffractive multifocal lens 1304 providing significantly lesscontrast sensitivity.

FIGS. 15A and 15B illustrate the pre-clinical dysphotopsia performancefor various lenses. FIG. 15A shows the normalized light intensityexhibited through the example lenses as a function of visual angle. Thereference monofocal aspheric lens 702 exhibits low intensity levelsaround the main image, while the example standard diffractive multifocallens 1204 exhibits relatively high intensity levels for differenteccentricities. FIG. 15A shows that three aspheric power progressivelenses 1502, 1504, and 1208 (H10 described in Tables 11-12) exhibitsimilar halo and glare performance (same light intensity distribution atvarious visual angles) than the monofocal aspheric lens 702. FIG. 15Bshows the actual images on which the numerical data at FIG. 15A arebased, showing intensity measurements of the reference asphericmonofocal lens 702 and the aspheric power-progressive lens 1504. Thesecomparisons demonstrate that the fitted aspheric power-progressive lensdesigns display significantly reduced dysphotopsia effects compared totraditional multifocal lenses.

Power Progressive Lenses with Extended Depth of Focus (EDF)

Embodiments herein disclosed also relate to lenses having a refractiveaspheric profile that provides a continuous power progression to extenddepth of focus (EDF) in combination with diffractive profiles. Powerprogressive refractive profiles can be defined according to Equation 1.

By way of example, FIG. 16 compares the power profile of apower-progressive, aspheric EDF lens 1602 to that of a monofocalspherical lens (spherical lens) 1604. The power progression of theexemplary lens Example 3 in FIG. 1 is created by a higher order aspherethat is positioned in the posterior IOL optic. The anterior IOL optic isalso aspheric and completely compensates for average corneal sphericalaberration. The profile is described by Equation 1 in combination withthe coefficients of Table 18.

TABLE 18 Coefficients describing the power progressive aspheric lenssurface Example 3 as applied in a posterior side of an ophthalmic lens Rk a₄ a₆ a₈ a₁₀ a₁₂ −12.9 −5.3E−01 2E−02 −9E−03 2E−03 −3E−04 2E−05

FIG. 16 shows that, while the spherical lens has a continuous power, thehigher order aspheric EDF profile determines a smooth power progressionfrom the center to the periphery. Due to the continuity of powerprogression, there are no zones in the lens. Therefore, the lens appearsvisually identical to a monofocal IOL when visually inspected. Becausethe power profile is different at any radial point of the lens surface,the refractive aspheric profile substantially differs from eitherspherical or zonal power refractive profiles.

FIG. 17 illustrates visual acuity by way of simulated defocus curvesprovided by the higher order aspheric profile of Example 3 (1602) and bythe comparative example spherical lens 1604, whose power profiles havebeen shown in FIG. 16. FIG. 17 shows that the progressive power profileresults in an extended depth of focus as compared to the spherical lens.The simulated visual acuity performance does not exhibit a bimodalperformance, indicating that the continuous power profile effectivelyextends depth of focus.

Table 19 describes a range of values for the parameters of a powerprogressive refractive profile positioned on the posterior lens surfacefor a lens with a base power between 18 D and 20 D. These ranges areapplicable when the anterior IOL lens surface is also aspheric andcompensates for corneal spherical aberration. According to Table 19, apower progressive refractive profile with the features described hereinhas a posterior radius between about 11 and 18 mm.

TABLE 19 Range of values for coefficients describing the powerprogressive refractive profile applied to the posterior surface of anIOL for base powers between 18 D and 20 D Lower Upper limit limit R −18−11 k −1 0.1 a₄ 0 0.05 a₆ −0.05 0 a₈ 0 0.01 a₁₀ −0.01 0 a₁₂ 0 0.0001

By way of example, FIG. 18 compares the power profile of a comparativemonofocal spherical lens 1604 to that of two aspheric EDF designs,Example 3 (1602) as described by Table 18 and Example 4 (1606), whosecoefficients are provided in Table 20, below. FIG. 18 shows that bothaspheric EDF designs provide a smooth power progression from the centerto the periphery, and providing a more pronounced power progression forExample 3 than for Example 4. The coefficients describing both Example 3and Example 4 are within the range of values shown in Table 19. Itshould be noted that the smaller in absolute value the radius of theaspheric design, the steeper the power progression, as illustrated bythe example provided in FIG. 18.

TABLE 20 Coefficients describing the power progressive lens surfaceapplied to the posterior side of the lens of Example 4 Design R k a₄ a₆a₈ a₁₀ a₁₂ Example 4 −16.3 −8.1E−02 7E−03 −4E−03 1E−03 −1E−04 7E−06

The ranges of coefficients described in Table 19 are applicable forrefractive power profiles with a base power between 18 D and 20 D. For agiven aspheric design, the range of base IOL powers can be expanded. Itis possible to create the full range of base powers of a givenrefractive EDF profile with a determined performance. For example, thedesign 1602 has a base power between 18 D and 20 D and defines adetermined power progression. The same relative power progression can beobtained for different base powers. Table 21 contains the coefficientsthat define the full range of base IOL powers with the relative powerprogression that defines the design 1604. Table 21 shows the ranges ofcoefficients describing a power progressive lens surface similar toExample 3 for a range of base powers between approximately 0 D and 50 D,or preferably between 0 D and 40 D, or more preferably from about 5 D toabout 34 D, from about 10 D to 30 D, or from 16 D to 28 D. The rangesshown in Table 21 correspond to possible expansions of the powerprogressive profile of Example 3.

TABLE 21 Range of values for coefficients describing a posterior powerprogression profile for different base powers Lower Upper limit limit R−30 −10 k −42 4 a₄ 0 0.05 a₆ −0.05 0 a₈ 0 0.01 a₁₀ −0.01 0 a₁₂ 0 1.0E−04

Alternatively, the higher order aspheric power-progressive lens surfacecan be imposed on the anterior lens surface while producing the same orsimilar continuous power progression. Table 22, below, shows theparameters describing continuous power progressive lens surface disposedon an anterior surface of an ophthalmic lens. Example 4a corresponds tothe anterior aspheric design, and Example 4 corresponds to the posteriordesign. FIG. 19 shows a graphical comparison 1900 between lens powerprofiles of Example 4 (1606), Example 4a (1608) and the monofocalspherical reference lens 1604. FIG. 19 illustrates that the powerprofiles of the posterior asphere Example 4 and its sibling anterioraspheric design Example 4a are virtually identical.

TABLE 22 Coefficients describing the power progression applied in theanterior optic in Example 4a Design R k a₄ a₆ a₈ a₁₀ a₁₂ Example 4a 10.33.0E−03 −8E−03 4E−03 −1E−03 1E−04 −7E−06Table 23, below, describes a range of values for the parametersdescribing power progression refractive profiles on the anterior lenssurface for a lens having a base power between 18 D and 20 D, when theposterior lens surface is spherical. A power progressive refractiveprofile with the features described herein can have a posterior radiusbetween 7 and 13 mm. Similarly as for the posterior surface, the greaterthe radius of the anterior aspheric design, the less pronounced thepower progression throughout the lens profile.

TABLE 23 Range of values for coefficients describing a power progressionprofile applied to an anterior side of a lens Lower limit Upper limit R7 13 k −1.5 0.05 a₄ −0.1 0.025 a₆ −0.05 0.025 a₈ −0.025 0.01 a₁₀ −0.0010.001 a₁₂ −0.0001 0.0001

Combined Diffractive and Power Progressive Refractive Lenses

Embodiments disclosed herein can provide an extended depth of focus(EDF). In some embodiments, diffractive intraocular lenses describedherein can also provide an EDF that results in a range of vision thatcovers distance, intermediate and/or near visual lengths with a betterimage quality than presently available multifocal lenses whilemitigating certain dysphotopsia effects, such as glare or halo.

Methods of manufacture for lenses and lens profiles as disclosed herein,as well as methods of treatment utilizing said diffractive andrefractive power-progressive lenses may include techniques described in,e.g., U.S. Pat. No. 9,335,563, entitled “MULTI-RING LENS, SYSTEMS ANDMETHODS FOR EXTENDED DEPTH OF FOCUS,” which is hereby incorporated byreference.

Diffractive lenses can make use of a material having a given refractiveindex and a surface curvature which provide a refractive power.Diffractive lenses affect chromatic aberration. Diffractive lenses havea diffractive profile which confers the lens with a diffractive power orpower profile that contributes to the overall depth of focus of thelens. The diffractive profile is typically characterized by a number ofdiffractive zones. When used for ophthalmic lenses these diffractivezones are typically annular lens zones, or echelettes, spaced about theoptical axis of the lens. Each echelette may be defined by an opticalzone, a transition zone between the optical zone and an optical zone ofan adjacent echelette, and echelette geometry. The echelette geometryincludes an inner and outer diameter and a shape or slope of the opticalzone, a height or step height, and a shape of the transition zone. Thesurface area or diameter of the echelettes largely determines thediffractive power(s) of the lens and the step height of the transitionbetween echelettes largely determines the light distribution between thedifferent powers. Together, these echelettes form a diffractive profile.The diffractive profile affects ocular chromatic aberration. Chromaticaberration can be increased or decreased depending on the morphology ofthe echelettes that compose the diffractive profile. The modification ofchromatic aberration can be at distance, intermediate, near and/or thecomplete range of vision provided by the diffractive profile.

A traditional multifocal diffractive profile on a lens may be used tomitigate presbyopia by providing two or more optical powers, forexample, one for near vision and one for far vision. The hybriddiffractive/refractive lenses disclosed herein provide an extended depthof focus across a range of optical powers. The lenses may take the formof an intraocular lens placed within the capsular bag of the eye,replacing the original lens, or placed in front of the naturalcrystalline lens. The lenses may also be in the form of a contact lens.

In specific embodiments, the refractive profile and diffractive profilemay be applied to the same side of the lens (e.g., both on a posteriorsurface of the lens, or both on an anterior surface of the lens); or maybe applied on opposite surfaces (e.g., with the diffractive profile onthe posterior surface and the refractive power-progressive profile onthe anterior surface).

According to some embodiments, a lens combining a diffractive profileand an aspheric power-progressive profile may have multiple diffractivezones. For example, a central zone of the lens may have one or moreechelettes at one step height and one phase delay, with a peripheralzone having one or more other echelettes at a different step heightand/or phase delay. According to a specific example (see Table 24,below), the central zone can have three echelettes and the peripheralzone has 6, providing for a total number of 9 echelettes within a lensof about 5 mm diameter. In the example, the step height of the centralzone is lower than in the peripheral zone. In an alternative embodiment,the step height of the central zone may be higher than in the peripheralzone. Alternatively, the step height may be the same throughout the lensprofile.

According to embodiments, a refractive power progressive and adiffractive profile occupy an entire working area, or optical area, ofthe lens. The minimum optical area of an IOL has a radius of about 2 mmaround the optical axis. In various embodiments, the optical area has aradius from about 2 mm to about 3 mm; or from about 2 mm to about 2.5mm. In a preferred embodiment, both the refractive profile and thediffractive profile occupy the entire optical area.

FIG. 20 is a graphical representation illustrating a combined asphericrefractive/diffractive lens profile 2000 according to some embodiments.The refractive component of the combined profile is a high order aspherethat results in a power progressive profile. The diffractive componentof the combined profile contains sets of zones, e.g., a central zone2001, and a peripheral zone 2003 that partially corrects for ocularchromatic aberrations.

The central zone 2001 in the example profile 2000 has three echelettes2002 having the same, first step heights 2005. The peripheral zone 2003has six echelettes 2004 having the same, second step heights 2006. Thetotal number of echelettes, and the step heights of the echelettes ineach zone, may vary. The central zone 2001 extends from a lens center2010 to a first position 2007 and the peripheral zone 2004 extends fromthe first position 2007 to a second position 2008 defined in terms ofthe radius of the lens. The specific attributes of an example lens D1(2000) are described below in Table 24:

TABLE 24 Diffractive Profile Parameters # of Phase Delay Step HeightExtension of D1 Echelettes (λ) (μm) the zone (mm) Central Zone 3 1.3 5.3(105) 1.42 Periphery 6 1.366 5.6 (106) 2.45

The diffractive profile in the example lens D1 has a phase delay between1 and 2λ for all of the echelettes. This phase delay has the effect ofcausing the diffractive profile to operate primarily in the first andsecond diffractive orders. As a consequence, the diffractive designpartially corrects ocular chromatic aberration. Phase delay can pertainto a single echelette; or can be ascribed to a group of echelettes eachhaving the same phase delay, where the group comprises a zone of thediffractive profile. Thus, phase delay can characterize singleechelettes, groups of echelettes, or an entire profile.

According to various embodiments, the number of diffractive echelettesfor a lens configured for a 5 mm pupil may range from 5 to about 14echelettes. The first echelette boundary can be positioned at a radiusof between 0.6 and 1.1 mm, with the remainder of the echelettes placedbetween the first echelette boundary and the lens periphery. Theposition of each subsequent echelette after the first echelette can bedetermined by the position of the first echelette multiplied by thesquare root of the respective echelette number.

Where the echelettes differ in phase delay between a central zone and aperipheral zone, the central zone can include between 1 and 5echelettes, or between 1 and 3 echelettes. The phase shift of echelettesin the peripheral zone may be greater than 1λ and smaller than 1.6λ, orbetween 1.2 and 1.4λ. The phase shift of the echelettes in the centralzone may be smaller, greater, or in some cases the same as in theperiphery. In some embodiments, the phase shifts of the centralechelettes may be 0.1 to 0.5λ smaller than, or greater than, the phaseshifts of echelettes in the periphery. Alternatively, a centralechelette or echelettes may have the same phase shift as echelettes inthe periphery, while a remainder of the rings in the central zone have agreater or smaller phase shift than the echelettes in the periphery,e.g. by about 0.1 to about 0.5λ.

In alternative embodiments, the phase delay may be between 2 and 3λ. Insuch an embodiment, the diffractive profile operates between the secondand third diffractive order. In such cases, the phase shifts of theperipheral zone should preferably be greater than 2λ and smaller than2.6λ, or between 2.2 and 2.4λ. The phase shift of the echelettes in thecentral zone may be smaller, greater, or in some cases the same as inthe periphery. In some embodiments, the phase shifts of the centralechelettes may be 0.1 to 0.5λ smaller than, or greater than, the phaseshifts of echelettes in the periphery. Alternatively, a centralechelette or echelettes may have the same phase shift as echelettes inthe periphery, while a remainder of the rings in the central zone have agreater or smaller phase shift than the echelettes in the periphery,e.g. by about 0.1 to about 0.5λ.

Light distribution is controlled by the step height between zones, suchthat a portion of the focusable light is directed to a distance focus,with most of the remainder of the light providing the extended depth offocus. The total light efficiency in the range of vision provided by thediffractive profile is approximately 93%. That efficiency results in alight loss of 7%, which is approximately 50% lower than a light losstypical for standard multifocal IOLs (which have light efficiencies ofapproximately 82%).

According to some embodiments, a hybrid, combined diffractive/powerprogressive refractive lens includes a combination of a diffractiveprofile, similar to the diffractive profile described above withreference to Table 24, with a refractive power progressive profile, asdescribed above with reference to, e.g., FIGS. 16-18. Performance of thehybrid or combined designs, as compared to a power-progressiverefractive component (Example 3) and as compared to a diffractive ERVcomponent (D1), is shown in the simulated VA curves 2100 of FIG. 21.FIG. 21 shows that the hybrid lens 2106 formed by a combination of apower-progressive refractive profile 2102 and diffractive profile 2104provides a depth of focus that is larger than the depth of focusachievable with either of the individual refractive or diffractiveprofiles alone.

In alternative embodiments, different refractive power progressiveprofiles may be provided for combination with the aforementioned, orother, diffractive profiles. For example, the depth of focus of thecombination can be controlled by providing a power progressive profilewith a more or less pronounced power progression.

For comparative purposes, FIG. 22 illustrates the simulated VA curves2200 of example lenses and lens components Example 4a (the progressivepower lens profile described above at Table 22) and D1 (the diffractiveERV lens profile described above in Table 24) alongside combined lensesutilizing D1 in combination with Example 4a. FIG. 22 shows that thehybrid combined lens profile 2206, which is formed by combining therefractive profile 2202 and diffractive profile 2204, provides a depthof focus that is larger than the depth of focus achievable with eitherof the individual refractive or diffractive profiles alone. However, thedepth of focus of the combination 2206 is substantially smaller than forthe hybrid, combined lens profile 2106 (FIG. 21). The longer depth offocus of the hybrid combined lens profile shown in FIG. 22 compared tothat of FIG. 21 is provided by the steeper power progression describedof the power progressive lens of Example 3 (FIG. 21).

In an alternative embodiment, a lens combining a diffractive profile andan aspheric power-progressive profile may have diffractive echeletteswith the same step height. For example, FIG. 23 is a graphicalrepresentation illustrating aspects of the diffractive component of acombined aspheric refractive/diffractive lens profile 2300 according tosome embodiments. The example profile 2300 has nine echelettes 2302having the same step heights 2304. In some specific embodiments, thefirst echelette 2302 a has a boundary positioned at about 0.79 mm fromthe optic center of the lens. However, it will be understood that theposition of the first echelette boundary, the total number ofechelettes, and the step heights and position of the echelettes, mayvary.

According to embodiments, the diffractive profile 2300 has a consistentphase delay through the optical zone. According to some embodiments, thephase delay is larger than 1λ and smaller than 2λ for all theechelettes. This profile provides for a diffractive profile thatoperates in predominantly in the first and second diffractive orders, sothat the lens partially corrects ocular chromatic aberration.

Specific embodiments of combined diffractive/refractive powerprogressive lenses are described in terms of visual acuity simulationsin FIGS. 24 and 25. According to one example, SM-1 is an examplediffractive lens profile with a diffractive part that has nineechelettes with common phase delays of 1.366λ and step heights of 5.6microns as shown below in Table 25. Alternative embodiments are alsoshown, i.e. SM-3, which is an example diffractive lens profile having aphase delay of 1.5, with step heights of 6.2 mm, respectively. Thepositions of the diffractive echelettes are the same for all embodimentspresented in Table 25.

TABLE 25 Diffractive Profile Parameters Diffractive Phase Delay Profile# of Echelettes (λ) Step Height (μm) SM-1 9 1.366 5.6 SM-3 9 1.5 6.2

In some (general) embodiments, phase delay can be larger than 1λ andsmaller than 2λ. In specific embodiments, phase delay can range fromabout 1.1λ up to 1.6λ, or from 1.2 to 1.5λ, The number of echelettes isdetermined based on the desired geometry of each echelette and theavailable radius. The number of echelettes may vary from as few as 5 toup to 10 in some specific embodiments; or in certain embodiments up to14. For example, for a lens configured for a pupil with a diameter of 5mm, the number of echelettes may range between 5 and 14 echelettes. Inspecific embodiments, the first echelette may be positioned with anechelette boundary between 0.6 and 1.1 mm from a center of the lens,with a remainder of the echelettes placed according the position of thefirst echelette multiplied by the square root of the echelette number.

In an alternative embodiment, the phase delays of the diffractiveechelettes may be between 2 and 3λ. In such cases, the diffractiveprofile operates between the second and third diffractive orders. Inspecific embodiments of lenses with echelettes having phase delaysbetween 2 and 3λ, the ranges for the phase shifts of the echelettes isgenerally greater than 2λ and smaller than 2.6λ, or preferably between2.2 and 2.5λ.

A hybrid, combined diffractive/power progressive refractive lens wasdeveloped by combining the diffractive profile described above withreference to Table 25 with the refractive power progressive profilesdescribed with reference to FIGS. 16-19. Various diffractive profilescan be combined with the refractive power-progressive profile in thismanner. For example, specific hybrid, combined diffractive/powerprogressive refractive lens profiles were developed (the combinedprofiles) by combining the diffractive profiles described above withreference to Table 25 with one or another of the refractive powerprogressive profiles described with reference to FIGS. 16-18.

For example, FIG. 24 shows simulated VA curves 2400 for the SM-1diffractive profile 2404 with a comparative, simulated VA curve for arepresentative power-progressive refractive design (refractive only)power-progressive lens surface, Example 3 2402. The performance of thecombined design 2406, which incorporates both profiles SM-1 and Example3, exhibits a broader range of visual acuity in the near andintermediate visual range (i.e. a longer depth of focus) than eithercomponent part.

Combined profiles based on SM-1, and SM-3 each provide for slightlydifferent distributions of light for distance vision n shown in Table26, below:

TABLE 26 Diffractive Profile Light Distribution to Distance Range, andTotal Light Efficiency in the Range of Vision Distance Range of VisionSM-1 0.62 0.93 SM-3 0.42 0.92

In Table 26, the SM-1 diffractive lens profile directs 62% of thefocusable light to the distance focal range. The light efficiency in therange of vision provided by the diffractive profile is approximately93%. That results in a light loss of 7%, which is approximately 50%lower than the light loss for a multifocal IOL operating in a similarrange (which has a light efficiency of approximately 82%).

The alternate embodiments, SM-3, exhibit a different light distributionprofile. SM-3, provides a greater distribution of light to extendeddepth of focus range (i.e., an extended range of vision including nearand intermediate distances) than SM-1. In all the cases, the lightefficiency in the total visual range (distance and extended depth offocus) is larger than that for traditional multifocal lenses.

For a given refractive power-progressive profile, the performance of thecombination depends on the diffractive profile. For diffractive profileswith a greater light distribution at the extended depth of focus, nearperformance is further enhanced when combined with the refractiveprofile. For example, FIG. 25 shows simulated VA curves 2500 for variouslenses incorporating the same power-progressive profile (Example 3) withdiffering diffractive profiles SM-1 (2406), and SM-3 (2506) inaccordance with embodiments. For example, the combinationdiffractive/power progressive refractive lens using the diffractiveprofile SM-3, which has an increased light distribution to the extendeddepth of focus range, provides increased performance at the intermediateand near region. In contrast, the combination with SM-1 provides betterdistance performance but a slightly shorter depth of focus.

Systems and Methods for Determining Lens Shape:

FIG. 26 is a simplified block diagram illustrating a system 2600 forgenerating a continuous progressive lens surface, such as the continuousprogressive lens surfaces 104 of FIG. 1 or 904 (FIG. 9), based on amultizonal surface, in accordance with embodiments. The system 2600 canbe used for generating other continuous progressive lens surfaces aswell, including lens surfaces configured for providing more than two orthree optical regimes. The system 2600 may, in some cases, be used togenerate a multizonal lens surface as an intermediate step to generatinga continuous progressive lens surface. The system 2600 may also be usedto produce IOLs conforming to a generated continuous progressive lenssurface. In some embodiments, the system 2600 can be used to produceIOLs including a diffractive profile that is combined with a continuouspower-progressive lens surface, either combined on the same surface(anterior or posterior) of the lens, or occupying opposite sides of thecontinuous progressive lens surface.

The system 2600 includes a user input module 2602 configured to receiveuser input defining aspects of an intraocular lens. Inputs to design anintraocular lens may include a patient's visual needs, cornealaberrations (or corneal topography, from which corneal aberrations canbe retrieved), a pupil size performance, and lens dimensions, amongother attributes. For example, the input can include a desired opticalpower profile for correcting impaired distance vision, a desired opticalpower profile for correcting impaired intermediate distance vision, adesired optical power profile for accommodating near distance vision,and any suitable combination of the above. In some cases, a desiredoptical power profile may relate to a patient's lifestyle, e.g., whetherthe patient prefers to participate in activities requiring predominantlydistance vision, intermediate vision, or near vision without additionalvisual correction. A multifocal prescription can be calculated from apatient's visual needs. The multifocal prescription can include, forexample, a preferred optical power or optical power profile forcorrecting far vision and an optical power or optical power profile fornear vision. In some cases, a multifocal prescription can furtherinclude an optical power or optical power profile for correctingintermediate vision, which may fall between the optical powers or rangesof optical powers described above. The corneal aberrations (or cornealwave front aberrations) can include the higher order rotationallysymmetrical aberrations of the cornea as a function of the pupil size. Apupil size performance can include a pupil diameter of a patient and thevision distance to be improved. These parameters can also be related topatient's life style or profession, so that the design incorporatespatient's visual needs as a function of the pupil size. In some cases,parameters such as the asphericity of a peripheral region can bedetermined based on a function of the wave front aberrations and visualneeds of the patient. Lens dimensions can include a preferred radius ofthe total lens, and may further include preferred thickness, or apreferred curvature of one or the other of the anterior surface andposterior surface of the lens.

A surface modeling module 2604 can receive information about the desiredlens from the user input module 2604, and can determine aspects of amultizonal lens. According to some embodiments, the surface modelingmodule 2604 includes a multizonal surface modeling module 2604 a, whichcan determine a multizonal lens profile according to a patient's visualneeds. According to some embodiments, the surface modeling module 2604can also include a diffractive surface modeling module 2604 b, which candetermine a diffractive lens profile also according to a patient'sneeds, preferably for combination with a refractive power-progressiveprofile.

For example, the multizonal surface modeling module 2604 a can determinethe shape of one or more zones of the multizonal lens, such as acurvature profile (e.g. spherical, aspheric) of each zone needed tofulfill the multifocal prescription, and the specific curvature of eachzone. The curvature of the outer zone can be related to the biometry ofthe patient, while the curvature of the intermediate zones can berelated with his visual needs in terms of intermediate and nearperformance. The asphericity of the outer zone can also be related tothat of the patient's cornea, so that it either compensates patient'scorneal spherical aberration or induces a certain amount of sphericalaberration to help improving intermediate and near performance inmesopic conditions. The multizonal surface modeling module 2604 a canfurther determine positions of zone boundaries. For example, themultizonal surface modeling module 2604 a can define an outer diameterof the lens, i.e. the lens periphery, based on desired lens dimensions.The multizonal surface modeling module 2604 a may further define aboundary between two or more optical zones based on the pupil size, theouter diameter of the lens, or both. In cases where there are more thantwo zones, the multizonal surface modeling module 2604 a can define therespective inner and outer radii of each zone based also on the numberof zones. The multizonal surface modeling module 2604 a can also defineheights of each respective zone, e.g. to match the heights of adjacentportions of each zone, such that an elevation profile of the lens iscontinuous.

The multizonal surface modeling module 2604 a can be configured togenerate performance criteria 2612, e.g. via modeling optical propertiesin a virtual environment. Performance criteria can include the match ofthe optical power profile of the multizonal lens with the desiredoptical power profile based on the multifocal prescription. Theperformance criteria can also include the severity of refractiveaberrations caused by the multizonal surface. In some cases, themultizonal surface modeling module 2604 a can provide an intraocularlens surface to an intraocular lens fabrication module for facilitatingthe production of a physical lens, which can be tested via anintraocular lens testing module 2610 for empirically determining theperformance criteria 2612, so as to identify optical aberrations andimperfections not readily discerned via virtual modeling, and to permititeration.

The multizonal surface modeling module 2604 a can provide a multizonalsurface to a surface generation module 2606, which can be configured toproduce a smooth aspheric surface such as the continuous powerprogressive lens surface 104 (FIG. 1). The surface generation module2606 can be configured to generate an elevation map of a multizonal lenssurface, and can fit an aspheric equation of the form of Equation 1 tothe elevation map via any suitable computational method forapproximating an empirical dataset. In some cases, the aspheric equationcan be fitted via a least-squares fitting method.

According to some embodiments, a diffractive surface modeling module2604 b can operate in tandem with the multizonal surface modeling module2604 a to generate a diffractive profile for combination with arefractive power progressive profile, according to the methods disclosedherein. The diffractive surface modeling module 2604 b can define adiffractive profile having specific echelette configurations, i.e.echelette numbers, positions, step heights, and phase delays, accordingto a patient visual need as provided by the user input module 2602. Byway of nonlimiting example, one such diffractive profile may be andiffractive EDF profile tuned to work in combination with a refractivepower progressive profile. Performance criteria 2612 can be assessed byeither or both of the multizonal surface modeling module 2604 a and thediffractive surface modeling module 2604 b.

As described above with respect to the surface modeling module 2604, thesurface generation module 2606 can also be configured to generateperformance criteria 2612. Performance criteria can include the match ofthe optical power profile of a continuous power progressive lens surfacegenerated by the surface generation module 2606 with the originalmultizonal surface. The above performance criteria may be weighted overlens regions that are spatially separate from the optical zone step ofthe original lens. In some cases, the surface generation module 2606 canalso provide a continuous power progressive lens surface to the lensfabrication module 2608 in order to produce an intraocular lens fortesting by the lens testing module 2610, so as to identify opticalaberrations, visual artifacts and imperfections not readily discernedvia virtual modeling, and to permit iteration. Iteration can includemodifying parameters of the fitting step (e.g., a degree of fit, amaximum order of terms of the fitting equation, a number and selectionof positions chosen for approximating the fit), and can also includeiteratively changing parameters of the multizonal surface at themultizonal surface modeling module 2604.

FIG. 27 is an example process 2700 for generating a continuous powerprogressive lens surface, in accordance with embodiments. The process2700 may be implemented in conjunction with, for example, the system2700 shown in FIG. 27. Some or all of the process 2700 (or any otherprocesses described herein, or variations, and/or combinations thereof)may be performed under the control of one or more computer systemsconfigured with executable instructions and may be implemented as code(e.g., executable instructions, one or more computer programs, or one ormore applications) executing collectively on one or more processors, byhardware or combinations thereof. The code may be stored on acomputer-readable storage medium, for example, in the form of a computerprogram comprising a plurality of instructions executable by one or moreprocessors. The computer-readable storage medium may be non-transitory.

The process 2700 includes receiving an input indicative of a patient'svisual needs (act 2702). The input can include, e.g., a desired opticalpower profile for correcting impaired distance vision, a desired opticalpower profile for correcting impaired intermediate vision, a desiredoptical power profile for accommodating near vision, and any suitablecombination of the above. Next, a first optical zone can be definedaccording to a first optical power profile indicated by the multifocallens prescription (act 2704). For example, the first zone can have apower profile suitable for correcting near and/or intermediate vision(i.e. a high relative power) and can be defined to include the center ofthe lens and extend to an outer perimeter of the first zone. Thediameter defining the outer perimeter of the first zone is sized suchthat a patient seeing through the lens would see light incident throughthe first zone as well as light incident from outside the first zone.Next, a second optical zone can be defined according to a second opticalpower profile also indicated by the multifocal lens prescription (act2706). In some cases, the second optical zone may be related to distancevision (i.e. a power profile for providing distance vision). In somecases, the second optical zone may have an aspheric profile suitable forcorrecting the corneal spherical aberration.

Next, the first and second optical zones can be merged to form a singlemultizonal surface (act 2708). A diameter defining the first opticalzone extends to an interior edge of the second optical zone, and anouter diameter of the second optical zone may extend to a periphery ofthe lens. However, in some cases, additional optical add zones may beprovided beyond the second. Generally, the first and second opticalzones are defined as concentric and radially symmetric about the opticalaxis of the lens, with the second optical zone bounding the firstoptical zone. The relative heights of the first optical zone and secondoptical zone are adjusted such that an elevation of the outer perimeterof the first optical zone matches an elevation of the inner perimeter ofthe second optical zone. If additional zones are included, then eachsuccessive outer perimeter can be matched with each successive innerperimeter to generate a continuous elevation profile from the center ofthe lens to the lens periphery.

The multizonal surface can then be fitted to a new, unique andcontinuous aspheric surface which approximates attributes of the zonesof the multizonal surface (act 2710). In some cases, fitting themultizonal surface to the continuous aspheric surface can includegenerating an elevation map of the multizonal surface, and performing acomputational fitting based on a high-order aspherical lens equationlike Equation 1, reproduced below, in which various high-ordercoefficients (e.g. a₁₀, a₁₂) are nonzero.

$Z = {\frac{{cr}^{2}}{1 + \sqrt{1 - {( {k + 1} )c^{2}r^{2}}}} + {a_{2}r^{2}} + {a_{4}r^{4}} + {a_{6}r^{6}} + {a_{8}r^{8}} + {a_{10}r^{10}} + {a_{12}r^{12}}}$However, various other methods of fitting a high-order aspheric equationto the multizonal surface are possible within the scope of thisdisclosure. The final surface generated by the process 2700 can becharacterized by a continuous function, such that a slope of anelevation map describing the generated surface is also continuous.

Where a purely refractive power-progressive lens is desired (i.e., not acombined diffractive/refractive lens) (act 2714), the system cangenerate instructions to fabricate an intraocular lens based on thegenerated aspheric surface (act 2712). However, in cases where acombined, or hybrid, diffractive/refractive power progressive lens isdesired, the system can further define a diffractive lens profileaccording to the patient's visual needs and for combination with a powerprogressive profile (act 2716). In some cases, the diffractive profilemay be defined for addition to a known power progressive profile; but inother cases, the specific diffractive profile and the specific powerprogressive refractive profile may be generated in an opposite order, orby an iterative process that incrementally adjusts both profiles toachieve the desired visual correction. A combined diffractive/powerprogressive refractive lens surface can then be generated based on theaspheric power-progressive profile and on the diffractive profile (act2718). This generation can include generating a lens surface that hasboth the diffractive and refractive power progressive components on thesame lens surface (e.g., posterior or anterior surface), or may providea total lens surface having the respective components positioned onopposite surfaces from each other. The surface features defined by thediffractive profile (e.g., diffractive echelettes) overlap with thefeatures defined by the refractive power-progressive profile (e.g., theaspheric surface). The system can then generate instructions tofabricate an intraocular lens based on the generated combineddiffractive/power progressive refractive lens surface (act 2720).

Additional Embodiments

In accordance with various embodiments, methods herein disclosed may beapplied for generating a wide variety of useful progressive in powerrefractive lens designs. The aspheric power progressive surface may beapplied for the anterior and posterior surface of the lensalternatively. Although several designs are included herein, changes inthe specific parameters defining each zone, as well as the number ofzones and the degree of spherical aberration may provide lens designstailored for a variety of uses, e.g. choosing optical performance forspecific distances, depths of focus, or other visual needs, inaccordance with embodiments.

In accordance with various embodiments, lens surfaces as disclosedherein may be applied to any suitable existing IOL design. Suitable IOLdesigns can include toric, monofocal, multifocal, extended range ofvision, and refractive-diffractive lenses, and combinations thereof. Insome cases, with suitable translation to a corresponding optical plane,methods of determining a lens shape can also be applied to cornealrefractive procedures. In alternative embodiments, designs hereindisclosed may also be applied to any suitable aspheric optical surface,e.g. IOLs, corneal inlays, and corneal onlays.

In various embodiments, diffractive designs can be added to lensesgenerated according to the techniques described above. Suitablediffractive designs can include designs for controlling chromaticaberration, to generate multifocal effects, and/or to extend depth offocus.

Computational Methods:

FIG. 28 is a simplified block diagram of an exemplary computingenvironment 2800 that may be used by systems for generating thecontinuous progressive lens surfaces of the present disclosure. Computersystem 2800 typically includes at least one processor 2852 which maycommunicate with a number of peripheral devices via a bus subsystem2854. These peripheral devices may include a storage subsystem 2856comprising a memory subsystem 2858 and a file storage subsystem 2860,user interface input devices 2862, user interface output devices 2864,and a network interface subsystem 2866. Network interface subsystem 2866provides an interface to outside networks 2868 and/or other devices,such as the lens fabrication module 2608 or lens testing module 2610 ofFIG. 26. In some cases, some portion of the above-referenced subsystemsmay be available in a diagnostics device capable of measuring thebiometric inputs required for calculating attributes such as base power.

User interface input devices 2862 may include a keyboard, pointingdevices such as a mouse, trackball, touch pad, or graphics tablet, ascanner, foot pedals, a joystick, a touchscreen incorporated into thedisplay, audio input devices such as voice recognition systems,microphones, and other types of input devices. User input devices 2862will often be used to download a computer executable code from atangible storage media embodying any of the methods of the presentinvention. In general, use of the term “input device” is intended toinclude a variety of conventional and proprietary devices and ways toinput information into computer system 2822.

User interface output devices 64 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may be a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or the like. The display subsystem may also provide a non-visualdisplay such as via audio output devices. In general, use of the term“output device” is intended to include a variety 20 of conventional andproprietary devices and ways to output information from computer system2822 to a user.

Storage subsystem 2856 can store the basic programming and dataconstructs that provide the functionality of the various embodiments ofthe present invention. For example, a database and modules implementingthe functionality of the methods of the present invention, as describedherein, may be stored in storage subsystem 2856. These software modulesare generally executed by processor 2852. In a distributed environment,the software modules may be stored on a plurality of computer systemsand executed by processors of the plurality of computer systems. Storagesubsystem 2856 typically comprises memory subsystem 2858 and filestorage subsystem 2860. Memory subsystem 2858 typically includes anumber of memories including a main random access memory (RAM) 2870 forstorage of instructions and data during program execution.

Various computational methods discussed above, e.g. with respect togenerating a fitted aspheric lens surface based on a multizonal lenssurface, may be performed in conjunction with or using a computer orother processor having hardware, software, and/or firmware. The variousmethod steps may be performed by modules, and the modules may compriseany of a wide variety of digital and/or analog data processing hardwareand/or software arranged to perform the method steps described herein.The modules optionally comprising data processing hardware adapted toperform one or more of these steps by having appropriate machineprogramming code associated therewith, the modules for two or more steps(or portions of two or more steps) being integrated into a singleprocessor board or separated into different processor boards in any of awide variety of integrated and/or distributed processing architectures.These methods and systems will often employ a tangible media embodyingmachine-readable code with instructions for performing the method stepsdescribed above. Suitable tangible media may comprise a memory(including a volatile memory and/or a non-volatile memory), a storagemedia (such as a magnetic recording on a floppy disk, a hard disk, atape, or the like; on an optical memory such as a CD, a CD-R/W, aCD-ROM, a DVD, or the like; or any other digital or analog storagemedia), or the like.

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of various embodiments of theinvention. In this regard, no attempt is made to show structural detailsof the invention in more detail than is necessary for the fundamentalunderstanding of the invention, the description taken with the drawingsand/or examples making apparent to those skilled in the art how theseveral forms of the invention may be embodied in practice.

The following definitions and explanations are meant and intended to becontrolling in any future construction unless clearly and unambiguouslymodified in the following examples or when application of the meaningrenders any construction meaningless or essentially meaningless. Incases where the construction of the term would render it meaningless oressentially meaningless, the definition should be taken from Webster'sDictionary, 3rd Edition or a dictionary known to those of skill in theart, such as the Oxford Dictionary of Biochemistry and Molecular Biology(Ed. Anthony Smith, Oxford University Press, Oxford, 2004).

As used herein and unless otherwise indicated, the terms “a” and “an”are taken to mean “one”, “at least one” or “one or more”. Unlessotherwise required by context, singular terms used herein shall includepluralities and plural terms shall include the singular.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words ‘comprise’, ‘comprising’, and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to”. Words using the singular or pluralnumber also include the plural and singular number, respectively.Additionally, the words “herein,” “above,” and “below” and words ofsimilar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of theapplication.

The description of embodiments of the disclosure is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.While the specific embodiments of, and examples for, the disclosure aredescribed herein for illustrative purposes, various equivalentmodifications are possible within the scope of the disclosure, as thoseskilled in the relevant art will recognize.

All references, including patent filings (including patents, patentapplications, and patent publications), scientific journals, books,treatises, technical references, and other publications and materialsdiscussed in this application, are incorporated herein by reference intheir entirety for all purposes.

Aspects of the disclosure can be modified, if necessary, to employ thesystems, functions, and concepts of the above references and applicationto provide yet further embodiments of the disclosure. These and otherchanges can be made to the disclosure in light of the detaileddescription.

Specific elements of any foregoing embodiments can be combined orsubstituted for elements in other embodiments. Furthermore, whileadvantages associated with certain embodiments of the disclosure havebeen described in the context of these embodiments, other embodimentsmay also exhibit such advantages, and not all embodiments neednecessarily exhibit such advantages to fall within the scope of thedisclosure.

While the above provides a full and complete disclosure of exemplaryembodiments of the present invention, various modifications, alternateconstructions and equivalents may be employed as desired. Consequently,although the embodiments have been described in some detail, by way ofexample and for clarity of understanding, a variety of modifications,changes, and adaptations will be obvious to those of skill in the art.Accordingly, the above description and illustrations should not beconstrued as limiting the invention, which can be defined by theappended claims.

What is claimed is:
 1. A method of designing an intraocular lens, themethod comprising: defining a first optical zone configured to place afirst focal distance of the intraocular lens, a first distance behindthe intraocular lens based on first set of criteria, the first opticalzone having an elevation profile that extends from a center of theintraocular lens to an outer periphery of the first optical zone, andhaving a power profile that extends from the center of the first opticalzone to the outer periphery of the first optical zone; defining a secondoptical zone configured to place a second focal distance of theintraocular lens, a second distance behind the intraocular lens, thesecond optical zone having an elevation profile that extends from aninner periphery of the second optical zone to an outer periphery of thesecond optical zone, and having a power profile that extends from theinner periphery of the second optical zone to the outer periphery of thesecond optical zone, wherein an elevation step is disposed between theelevation profile of the first optical zone at the outer periphery ofthe first optical zone and the elevation profile of the second opticalzone at the inner periphery of the second optical zone, and wherein anoptical power step is disposed between the power profile of the firstoptical zone at the outer periphery of the first optical zone and thepower profile of the second optical zone at the inner periphery of thesecond optical zone; merging the first optical zone with the secondoptical zone, such that the elevation step is eliminated and the opticalpower step is retained; and generating an aspheric surface for theintraocular lens based on the merged first optical zone and secondoptical zone, the aspheric surface being defined by a single asphericequation, such that the aspheric surface for the intraocular lensapproximates the first optical zone across a first region of theintraocular lens and approximates the second optical zone across asecond region of the intraocular lens, and such that the asphericsurface of the intraocular lens defines an intraocular lens powerprofile that varies as a continuous function of a radial distance fromthe center of the intraocular lens from a first power at a center of theintraocular lens to a base power at a periphery of the intraocular lens,whereby there is no optical power step along the intraocular lens powerprofile.
 2. The method of claim 1, wherein the power profile of thefirst optical zone is defined by a constant function.
 3. The method ofclaim 1, wherein the power profile of the second optical zone is definedby an aspheric function.
 4. A method of designing an intraocular lens,the method comprising: defining a first optical zone configured to placea first focal distance of a lens a first distance behind the lens basedon a first set of criteria; defining a second optical zone configured toplace a second focal distance a second distance behind the lens, thesecond optical zone being different from the first optical zone; mergingthe first optical zone with the second optical zone, such that a firstelevation of an outer periphery of the first optical zone corresponds toa second elevation of an inner periphery of the second optical zone; andgenerating an aspheric surface based on the merged first optical zoneand second optical zone, the aspheric surface being defined by a singleaspheric equation, such that the aspheric surface approximates the firstoptical zone across a first region of the lens and approximates thesecond optical zone across a second region of the lens, and such thatthe intraocular lens power profile varies smoothly with a radialdistance from the center of the lens from a maximum power at a center ofthe lens to a base power at a periphery of the lens.
 5. The method ofclaim 4, wherein the single aspheric equation can be expressed as:${Z = {\frac{{cr}^{2}}{1 + \sqrt{1 - {( {k + 1} )c^{2}r^{2}}}} + {a_{2}r^{2}} + {a_{4}r^{4}} + {a_{6}r^{6}} + {a_{8}r^{8}} + {a_{10}r^{10}} + {a_{12}r^{12}}}},$and wherein at least the a₄, a₆, and a₈ terms are nonzero.
 6. The methodof claim 5, wherein at least the a₁₀ term is nonzero.
 7. The method ofclaim 5, wherein at least the a₁₀ and a₁₂ terms are nonzero.
 8. Themethod of claim 4, wherein defining the first optical zone furthercomprises selecting a first optical zone diameter based in part on asize of a patient's pupil.
 9. The method of claim 4, wherein definingthe first optical zone further comprises selecting a first optical zonediameter based in part on a patient's visual needs.
 10. The method ofclaim 4, wherein defining the first optical zone further comprisesselecting a first optical zone diameter based in part on a patient'slifestyle preference.
 11. The method of claim 4, wherein defining thesecond optical zone further comprises selecting a second optical zonewith a defined spherical aberration based in part on a patient's visualneeds.
 12. The method of claim 4, wherein defining the first opticalzone further comprises selecting a first optical zone diameter forimproving one of: distance vision, intermediate vision, or near vision.13. The method of claim 4, wherein defining the first optical zonefurther comprises selecting a first optical zone power for optimizingone of: distance vision, intermediate vision, or near vision.
 14. Themethod of claim 4, further comprising: defining a third optical zoneconfigured to place a third focal distance of the lens a third focaldistance behind the lens; and merging the third optical zone with thesecond optical zone, such that a third elevation of an outer peripheryof the second optical zone corresponds to a fourth elevation of an innerperiphery of the third optical zone; wherein generating the asphericsurface further comprises fitting the single aspheric equation to thefirst, second, and third optical zones such that the single asphericequation further approximates the third optical zone across a thirdregion of the lens, the third region being concentric with the first andsecond regions.
 15. The method of claim 14, wherein fitting the first,second, and third optical zones to the single aspheric equationcomprises performing a least-squares fitting of a first equationdefining the first optical zone across a first diameter, a secondequation defining the second optical zone across a second diameter, anda third equation defining the third optical zone across a thirddiameter.
 16. The method of claim 14, wherein fitting the first, second,and third optical zones to the single aspheric equation comprisesgenerating an elevation map of a discontinuous lens comprising thefirst, second, and third optical zones, and generating a least squaresfitting based on the elevation map.
 17. The method of claim 14, whereinfitting the first, second, and third optical zones to the singleaspheric equation comprises generating an elevation map of adiscontinuous lens comprising the first, second, and third opticalzones, and generating a least squares fitting based on the elevation mapto the equation:$Z = {\frac{{cr}^{2}}{1 + \sqrt{1 - {( {k + 1} )c^{2}r^{2}}}} + {a_{2}r^{2}} + {a_{4}r^{4}} + {a_{6}r^{6}} + {a_{8}r^{8}} + {a_{10}r^{10}} + {a_{12}{r^{12}.}}}$18. The method of claim 4, wherein fitting the first and second opticalzones to the single aspheric equation comprises performing aleast-squares fitting of a first equation defining the first opticalzone across a first diameter and a second equation defining the secondoptical zone across a second diameter.
 19. The method of claim 4,wherein fitting the first and second optical zones to the singleaspheric equation comprises generating an elevation map of adiscontinuous surface comprising the first and second optical zones, andgenerating a least squares fitting based on the elevation map.